In the glass producing industry, particulate matter comprising the glass batch is pelletized employing an aqueous solution; the pellets are dried and preheated by contact with hot gases and the hot pellets are introduced into a melter in which they are melted to form molten glass which, in turn, is converted into glass fibers.
Generally, there are two steps involved in bringing the pellets up to the described temperature. The first is a drying step in which the aqueous content of the pellets is expelled by contact with gases at a relatively low temperature. In the second step, the dried pellets are heated to as high a temperature as desired, consistent with the temperature of the hot gases with which they are contacted. In order to best carry out the preheating step, it is desirable that a process be employed which provides for control of the temperature of the hot gases as well as providing some agitation of the pellets, themselves, so that heat transfer between the hot gases and the pellets is maximized by providing intimate contact of the hot gases with a maximum surface of the pellet and insure that pellets remain free flowing.
There has now been developed a process and apparatus which will accomplish this by providing movement of both the pellets and the hot gases while in contact with each other; the contact which results will be greater than that which occurs when the only contact is that which occurs when the pellets move downward as a moving bed in a reactor and into contact with hot gases moving upwardly therethrough.